The heart of a computer is a magnetic hard disk drive (HDD) which typically includes a rotating magnetic disk, a slider that has read and write heads, a suspension arm above the rotating disk and an actuator arm that swings the suspension arm to place the read and/or write heads over selected circular tracks on the rotating disk. The suspension arm biases the slider into contact with the surface of the disk when the disk is not rotating but, when the disk rotates, air is swirled by the rotating disk adjacent an air bearing surface (ABS) of the slider causing the slider to ride on an air bearing a slight distance from the surface of the rotating disk. When the slider rides on the air bearing the write and read heads are employed for writing magnetic impressions to and reading magnetic signal fields from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
The volume of information processing in the information age is increasing rapidly. In particular, HDDs have been desired to store more information in its limited area and volume. A technical approach to this desire is to increase the capacity by increasing the recording density of the HDD. To achieve higher recording density, further miniaturization of recording bits is effective, which in turn typically requires the design of smaller and smaller components.
High recording performance, high reliability, and low manufacturing cost are extremely useful attributes for magnetic recording heads used in HDDs. Japanese Unexamined Patent Application Publication No. 2008-300027 discloses a perpendicular magnetic recording head that is able to provide these attributes. The perpendicular magnetic recording head, according to this publication, includes at least a main pole, a lower shield positioned below the main pole, and side shields positioned on sides thereof.
Recording reliability is obtained due to the shields being disposed below and to the sides of the main pole which prevent erroneous reading of adjacent or nearby tracks, such as erroneous reading due to adjacent track interference (ATI), far track interference (FTI), etc. High reliability is realized by increasing the laminate of the magnetic body of the main pole.
It is well known that to produce magnetic heads at a low cost depends greatly on the manufacturing method utilized. Low manufacturing costs may be accomplished by embedding the main pole in a groove produced via an etching process performed on an upper surface of the lower shield. In order to perform this etching process, U.S. Patent Application Publication Nos. 2011/0151279 and 2011/0134569 disclose a structure in which a taper is provided on a trailing side and a leading side of the main pole in a down-track direction.
However, even with this structure, there is concern that erroneous reading of an adjacent track or nearby tracks due to ATI or FTI may occur. Accordingly, a magnetic head which alleviates these concerns would be very beneficial.